// Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <stdio.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/types.h>
#include "paddle/extension.h"

#define MAX_BSZ 256

// #define SAVE_WITH_OUTPUT_DEBUG
#define MAX_DRAFT_TOKENS 6
struct msgdata {
  long mtype;  // NOLINT
  int mtext[2 + MAX_BSZ +
            MAX_BSZ * MAX_DRAFT_TOKENS];  // stop_flag, token_num, tokens
};

void MTPSaveFirstToken(const paddle::Tensor& x,
                       const paddle::Tensor& not_need_stop,
                       int64_t rank_id,
                       int msg_queue_id,
                       bool save_each_rank) {
  if (!save_each_rank && rank_id > 0) {
    return;
  }
  int x_dim = x.shape()[1];
  auto x_cpu = x.copy_to(paddle::CPUPlace(), false);
  int64_t* x_data = x_cpu.data<int64_t>();
  static struct msgdata msg_sed;

  if (const char* inference_msg_queue_id_env_p =
          std::getenv("INFERENCE_MSG_QUEUE_ID")) {
    std::string inference_msg_queue_id_env_str(inference_msg_queue_id_env_p);
    int inference_msg_queue_id_from_env =
        std::stoi(inference_msg_queue_id_env_str);
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Your INFERENCE_MSG_QUEUE_ID is: "
              << inference_msg_queue_id_from_env << std::endl;
#endif
    msg_queue_id = inference_msg_queue_id_from_env;
  }
  static key_t key = ftok("./", msg_queue_id);
  static int msgid = msgget(key, IPC_CREAT | 0666);

  msg_sed.mtype = 1;
  bool not_need_stop_data = not_need_stop.data<bool>()[0];
  int inference_msg_id_from_env = 1;
  if (const char* inference_msg_id_env_p = std::getenv("INFERENCE_MSG_ID")) {
    std::string inference_msg_id_env_str(inference_msg_id_env_p);
    inference_msg_id_from_env = std::stoi(inference_msg_id_env_str);
    if (inference_msg_id_from_env == 2) {
      // 2 and -2 is preserve for no-output indication.
      throw std::runtime_error(
          " INFERENCE_MSG_ID cannot be 2, please use other number.");
    }
    if (inference_msg_id_from_env < 0) {
      throw std::runtime_error(
          " INFERENCE_MSG_ID cannot be negative, please use other "
          "number.");
    }

#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Your INFERENCE_MSG_ID is: " << inference_msg_id_from_env
              << std::endl;
#endif
  } else {
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Failed to got INFERENCE_MSG_ID at env, use (int)1 as default."
              << std::endl;
#endif
  }
#ifdef SAVE_WITH_OUTPUT_DEBUG
  std::cout << "save_output_key: " << key << std::endl;
  std::cout << "save msgid: " << msgid << std::endl;
#endif
  msg_sed.mtext[0] = not_need_stop_data ? inference_msg_id_from_env
                                        : -inference_msg_id_from_env;
  int bsz = x.shape()[0];
  msg_sed.mtext[1] = bsz;
  for (int i = 0; i < bsz; i++) {
#ifdef SAVE_WITH_OUTPUT_DEBUG
    printf("bid: %d. 1: %d. 2: %d.\n",
           i,
           static_cast<int>(x_data[i * x_dim]),
           static_cast<int>(x_data[i * x_dim + 1]));
#endif
    msg_sed.mtext[i + 2] = 2;
    msg_sed.mtext[i * MAX_DRAFT_TOKENS + 2 + MAX_BSZ] =
        static_cast<int>(x_data[i * x_dim]);
    msg_sed.mtext[i * MAX_DRAFT_TOKENS + 1 + 2 + MAX_BSZ] =
        static_cast<int>(x_data[i * x_dim + 1]);
#ifdef SAVE_WITH_OUTPUT_DEBUG
    printf("mtext[%d]:%d. mtext[%d]:%d. \n",
           i * MAX_DRAFT_TOKENS + 2 + MAX_BSZ,
           msg_sed.mtext[i * MAX_DRAFT_TOKENS + 2 + MAX_BSZ],
           i * MAX_DRAFT_TOKENS + 1 + 2 + MAX_BSZ,
           msg_sed.mtext[i * MAX_DRAFT_TOKENS + 1 + 2 + MAX_BSZ]);
#endif
  }

#ifdef SAVE_WITH_OUTPUT_DEBUG
  std::cout << "msg data: ";
  for (int i = 0; i < bsz; i++) {
    std::cout << " " << static_cast<int>(x_data[2 * i]) << " ";
    std::cout << " " << static_cast<int>(x_data[2 * i + 1]);
  }
  std::cout << std::endl;
#endif
  if ((msgsnd(msgid,
              &msg_sed,
              (2 + MAX_BSZ + MAX_BSZ * MAX_DRAFT_TOKENS) * 4,
              0)) == -1) {
    printf("full msg buffer\n");
  }
  return;
}

void MTPSaveFirstTokenStatic(const paddle::Tensor& x,
                             const paddle::Tensor& not_need_stop,
                             int64_t rank_id,
                             bool save_each_rank) {
  MTPSaveFirstToken(x, not_need_stop, rank_id, 1, save_each_rank);
}

void MTPSaveFirstTokenDynamic(const paddle::Tensor& x,
                              const paddle::Tensor& not_need_stop,
                              int64_t rank_id,
                              int msg_queue_id,
                              bool save_each_rank) {
  MTPSaveFirstToken(x, not_need_stop, rank_id, msg_queue_id, save_each_rank);
}

PD_BUILD_OP(mtp_save_first_token)
    .Inputs({"x", "not_need_stop"})
    .Attrs({"rank_id: int64_t", "save_each_rank: bool"})
    .Outputs({"x_out"})
    .SetInplaceMap({{"x", "x_out"}})
    .SetKernelFn(PD_KERNEL(MTPSaveFirstTokenStatic));

PD_BUILD_OP(mtp_save_first_token_dynamic)
    .Inputs({"x", "not_need_stop"})
    .Attrs({"rank_id: int64_t", "msg_queue_id: int", "save_each_rank: bool"})
    .Outputs({"x_out"})
    .SetInplaceMap({{"x", "x_out"}})
    .SetKernelFn(PD_KERNEL(MTPSaveFirstTokenDynamic));
